1. Technical Field
The present disclosure generally relates to a microfluidic device, and more particularly to a microfluidic device suitable for encapsulation of pharmaceutical, flavors, fragrances and the like by forming polymersomes and liposomes as encapsulation and delivery agents, viscosity modifiers and/or thickening agents.
2. Background Art
In general, polymersomes represent a class of vesicles, tiny hollow spheres that enclose a solution. Polymersomes are typically made using amphiphilic synthetic block copolymers to form the vesicle membrane, and generally range from about 50 nm to about 5 um in radius or more. Polymersomes generally contain an aqueous medium in their core and are useful for encapsulating and protecting sensitive molecules, such as, for example, drugs, enzymes, other proteins and peptides, and DNA and RNA fragments. In general, the polymersome membrane provides a physical barrier that isolates the encapsulated material from external materials, such as those found in biological systems.
Polymersomes are similar to liposomes, which are formed from naturally occurring lipids. While having many of the properties of natural liposomes, polymersomes typically exhibit increased stability and reduced permeability. Furthermore, the use of synthetic polymers allows manipulation of the characteristics of the membrane and thus control permeability, release rates, stability and other properties of the polymersome.
Encapsulated actives such as fragrances, flavors, pharmaceutical materials, etc., may be used in a variety of cosmetic, pharmaceutical and food related areas. Such applications include, but are not limited to, fragrance, drug and flavor encapsulation using well-defined particle size encapsulation agents. Polymersomes containing active enzymes that provide a way to selectively transport substrates for conversion have been described as nanoreactors and have been used to create controlled release drug delivery systems while being substantially invisible to the immune system.
There are various methods to protect active compounds from environmental and processing conditions, avoid loss of volatiles and release actives at desired times. Active encapsulation generally requires using a carrier material for protection, delivery and controlled release. Liposomes and polymersomes can be used as active delivery agents. Successful encapsulation processes require high encapsulation efficiency, protection of actives from unfavorable process and storage conditions and favorable release mechanisms.
Liposomes are used in various cosmetics applications such as cosmetic stick formulations and anhydrous spray formulations. Liposome encapsulated actives are generally spray dried with other hydrocolloids and dispersed in various formulations. Successful encapsulation in the fragrance industry, for example, for hair care products, depends on factors such as availability, cost and compatibility of ingredients and deposition of the actives onto hair. The active should survive washing, rinsing and even drying of hair. Even though liposomes have been used extensively for delivery and deposition of actives onto the hair, they may have limitations in terms of shelf life and after administration. However, polymersomes or nanoparticles of lipids/polymers may overcome some limitations experienced with liposomes. In general, polymersomes are tougher and stronger than liposomes. The ability to modify the surface of liposomes and polymersomes with anchoring molecules may enhance the survival of actives during various stages of use.
Encapsulation of flavors has enjoyed numerous available techniques. Spray drying and extrusion are some common encapsulation techniques. These processes generally require high temperature exposure, and heat and/or oxygen sensitive flavors are adversely affected from these methods. Other techniques are freeze drying and hot melting. Liposomes are also used as flavor encapsulation agents.
Encapsulation of physiologically active compounds can enhance bioavailability and therapeutic index over extended time scales. Lipid and polymer based drug delivery systems utilize the ability to form micro-spheres. These micron size particles can be used for a variety of purposes ranging from direct injection to aerosols for inhalation. Unilamellar and multilamellar liposomes have also been used as lipid-based drug delivery systems.
Currently, polymersomes are made nearly exclusively by a process of film rehydration. The method involves simply the spontaneous budding off of polymersomes from a polymer surface. It is a slow process and with very low levels of material encapsulation. This process provides little control of polymersome size or membrane thickness and loading is inefficient. It is believed that polymersomes are currently not used commercially due to these problems.
One known device is used to make polymersomes by microfluidics using opposing fluid flows. The device is tedious to produce with a high failure rate. It is fragile, and has not been shown to allow control of size or membrane thickness of the polymersomes produced.
In view of the various known beneficial uses of polymersomes as useful carriers for targeted medication and the lack of suitable ways to prepare them, it is desirable to provide an improved apparatus to prepare polymersomes and its method of its use. These and other inefficiencies and opportunities for improvement are addressed and/or overcome by the systems and methods of the present disclosure.